# SchemaHD vs Simple Sequence Diagram AI

The clearest difference is device support: Simple Sequence Diagram AI at 4 against SchemaHD's 1. On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. SchemaHD sells 7 one-off in-app purchases and Simple Sequence Diagram AI sells 2 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.

SchemaHD ships an update every 10 days, Simple Sequence Diagram AI every 2 weeks. The most recent releases landed on November 3, 2026 and November 8, 2026 respectively.

## The numbers

| Metric | SchemaHD | Simple Sequence Diagram AI |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.0 (2 ratings)](https://appshunter.io/ios/app/schemahd/id1578851758/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 10 days** | Every 2 weeks |
| Monetization | Free | — |
| Size | 2 MB | 55 MB |
| Requires iOS | **14.0** | 15.6 |
| Devices | iPad | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Yasuaki Iwasaki](https://appshunter.io/developer/560857505) | [YUKI TANAIKE](https://appshunter.io/developer/478558546) |

## What reviewers say

### SchemaHD

[App page](https://appshunter.io/ios/app/schemahd/id1578851758)

This app allows users to draw circuit diagrams for logic circuits, generating Verilog HDL and performing simulations. It simplifies FPGA development by using schematics instead of complex programming languages, offering advanced security and high-performance parallel processing.

**Highlights:** Draw logic circuit diagrams, Generate Verilog HDL, Perform circuit simulations, Touch-based wiring, AXI bus interface support, JSON import/export, Offline network operation

**Features:** macOS Compatibility

**In-app purchases (7)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Give a tip #1 | $1.99 | one-time |
| Give a tip #2 | $3.99 | one-time |
| Give a tip #3 | $7.99 | one-time |
| Give a tip #4 | $15.99 | one-time |
| Give a tip #5 | $23.99 | one-time |
| Give a tip #6 | $39.99 | one-time |
| Give a tip #7 | $79.99 | one-time |


### Simple Sequence Diagram AI

[App page](https://appshunter.io/ios/app/simple-sequence-diagram-ai/id6711357061)

**Features:** Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Simple Sequence Flow Pro (Monthly) | $4.99 | per month |
| Simple Sequence Flow Pro (Annual) | $44.99 | per year |


## Frequently asked questions

### Is SchemaHD free?

SchemaHD is free to download, with in-app purchases available.

### Is Simple Sequence Diagram AI free?

Simple Sequence Diagram AI is free to download, with in-app purchases available.

### Do SchemaHD or Simple Sequence Diagram AI have ads?

Neither SchemaHD nor Simple Sequence Diagram AI shows ads.

### Which is updated more often, SchemaHD or Simple Sequence Diagram AI?

SchemaHD ships an update every 10 days, and Simple Sequence Diagram AI every 2 weeks. Most recently, SchemaHD was updated on November 3, 2026 and Simple Sequence Diagram AI on November 8, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*